In the past two years the tech gadget market has been flooded with a wide array of wearable personal activity trackers. The Fitbit, Garmin’s Vivofit and VivoSmart lines and Pebble are just a few of the 10-15 different brands each with several different models. Most trackers include the same basic functionality such as step counting, sleep tracking, smartphone notifications, heart rate tracking, and other activity tracking. In reality they are really just glorified pedometers. The reason for the flood of these gadgets on the market is predominately due to two reasons: the simplicity of the technology used; and their popularity for people wanting to be active and healthy throughout the day when they’re not blasting their glutes at the gym. This post will cover some of the experiences I’ve had using my first activity tracker, the Garmin Vivosmart. While it may read like a review of that particular model, I’ve tried to keep it general so as to apply to the common features of most activity trackers out there.
Step tracking is the bread the butter of most activity trackers. In almost all devices steps are tracked using a built-in accelerometer and make use of an algorithm which is supposed to help distinguish between regular movement of the arms and actual steps. In my experience with the Garmin Vivosmart, the step tracker has a wide range of accuracy. For the most part it can tell the difference between small bumps and jostles when driving or sitting on the bus and other such activities but with more accentuated movement, it starts to get a bit dodgy. First, I wear my tracker on my left hand, which happens to be my dominate hand, so I find that brushing my teeth, washing my hair, doing dishes, and pretty much any activity that involves repetitive use of the dominate hand, I earn several steps when I shouldn’t. I estimate that about 5-10% of my daily steps comes from these non-step movements. I could probably reduce some of this noise by switching the tracker to my other hand. On the other hand, so to speak, when I was in Costa Rica recently, I managed to hit my 12,000 step daily goal while sitting on a bus from Monte Verde to Samara just because of how bumpy and long the ride was. So far there seems to be no way to pause the tracking ability while driving in order to alleviate this problem.
As for the usefulness of tracking steps, I’m unsure. Certainly for athletes step tracking isn’t all that useful. It’s really meant more for people with office jobs or those who are generally sedentary throughout the day. It is motivating to try and hit my daily step goal and I do find myself getting off the couch and walking around the apartment to reset my inactivity alarm (which requires 100 steps for every hour of inactivity up to 200 steps). But in general I can’t see it being the kick many people need to change their habits. Logging steps around the office is good but it won’t necessarily make you a healthier person. It’s a good starting point and it does provide positive feedback that can be motivating to get off the couch or away from the cubicle but on its own, it doesn’t do much to improve quality of life.
Almost all activity trackers track sleep using the same technology that tracks steps namely an accelerometer. The accelerometer measures the amount of movement during sleep in order to gauge when the person was in a deep sleep, when they were in a light sleep, and when they are awake. This is based on the premise that when in deep REM sleep people move very little. The only way to truly identify deep sleep from light is to measure a variety of metrics, which include (but are not limited to) heart rate, brain activity, body temperature and movement. So how accurate is sleep tracking using movement alone? In my own experience it seems to be reasonable. I can’t attest to how well it actually tracks deep sleep and light sleep but in general when I feel like I’ve had a good sleep, my tracker will show higher amounts of deep sleep. The primary criticism with sleep tracking is its benefit. Why do we need to know how well we slept when most of us have a general idea of how well we slept by how well we feel in the morning? It’s a bit like trying to track someone’s enjoyment of something by hooking a bunch of electrodes to their brain instead of just asking, ‘Did you enjoy that?’.
For most people the sleep-tracking feature is largely useless but mildly interesting to see your subjective perception of your sleep quantified on a screen. I would argue that for athletes it has some potential benefits.
- If the tracker accurately measures sleep time, which I have found it does do well, it is possible to use that data alone to aid performance analysis over time. Cross referencing data points with performance is always a good way to see how variables, like sleep, play a role in athletic performance over time.
- There is marked difference in how we can feel in the first 30-60min if we wake during deep sleep versus light sleep. In general we go through several deep and light sleep cycles throughout the night with each cycle lasting up to 90 minutes. If we wake during a period of light sleep we tend to feel more alert and refreshed immediately after waking up regardless of how well we slept throughout the whole night. The opposite is true if we wake during a deep sleep. We tend to feel drowsy and groggy even if we had a good night sleep. I have found sleep tracking useful in situations where I do early morning workouts. Sometimes if I wake up feeling groggy and tired, I may opt to skip my early morning workout thinking that I’m too fatigued from the previous day’s efforts. With sleep tracking I can roughly gauge how well I slept and what sleep cycle I woke from. This way I can discern whether I am indeed still fatigued or if I am simply feeling the effect of waking up during a deep sleep cycle and just need a few minutes to shed the grogginess.
Some trackers, like mine, feature activity tracking that goes beyond just steps and sleep. I can track my runs with the Vivosmart and I can even link my ANT+ heart rate strap and my ANT+ Speed/Cadence sensor to the Vivosmart to track my running and cycling activity. ANT+ connectivity and the ability to track other activities besides steps is a step, so-to-speak, in the right direction towards making activity trackers a must-have wearable. Garmin has clearly caught on to this but there are still limitations to making it truly a useful feature. First, in order to record heart rate or speed/cadence information, the user has to start an activity manually and record it as separate activity on the Garmin Connect software. I.e. if you go for a bike ride, you press start when you hop on, and press stop and save when you’re done. That’s all fine and dandy but when you consider that most serious cyclists and runners will have a dedicated cycling computer (like an Edge 500) and/or running watch (like a Forerunner) they probably aren’t going to need to record their activity on their step tracker. They also probably want more metrics (like GPS track) than just HR and spd/cad. For that reason I don’t find the ANT+ connectivity all that useful. If you’re a casual cyclist (perhaps a commuter or just want to record your trip to the shops) or run once in awhile to get some cardio, you probably haven’t bothered to invest in a heart rate strap or speed/cadence sensor and thus these features won’t be of much use to you either. The one area I did find use for the HR strap was while on vacation. Rather than bring my expensive GPS enabled running watch to track my runs while backpacking in Costa Rica and Europe, I used my Vivosmart and the HR strap to track my activity (if nothing to else so I could log my calories). Where Garmin could make these features more useful is for people like me who have speed/cadence on their commuter and street bikes. Rather than have to manually start/stop an activity it would be great if the Vivosmart tracked kilometers once it picks up the signal from the sensor just like it tracks steps. So rather than the ride showing up as a new activity, it just assumes I’m on the bike whenever the sensor reads a speed of more than 0.0kph. This way I can track my cycling distances from booting around town without having to have my Edge 500 or having to constantly be starting and stopping activities on the Vivosmart. Tracking sites like Strava already make a distinction between ‘bike rides’ and ‘commuting’ so it would be smooth integration to be able to track both actual bikes rides as separate activities and have a running tally of overall distance cycled which includes all of my little trips to the local craft brewery.
The primary benefit, in my opinion, and the reason I still wear my Vivosmart is the connectivity between my phone and the tracker. The ability to receive phone alerts on my wrist while my phone is tucked in my pocket is great. I’m one of those people who constantly check my phone because I’m a raging social media junkie. Being able to quickly glance at my watch to see if I have a Facebook notification or an email without pulling out my phone is grand. It makes me seem less like a stereotypical anti-social millennial and more like a guy obsessed with punctuality (because it looks like I’m just checking my watch). A tracker without smartphone integration is a pointless purchase in my opinion. The other features are useful, but they aren’t enough on their own (just as smartphone integration on its own wouldn’t be worth it). The more [useful] features a tracker can have in that tiny little band, the more it will be worth keeping on my person at all times.
Activity trackers have certainly gained traction in the tech market and I don’t see them going away anytime soon, particularly with the rapid advancement in personal wearable technology. They will only become more useful as times goes on. For now, if you’re thinking about buying one, make sure it has a plethora of [useful] features and maybe wait until it goes on sale.